Marijuana legalization may be the same-sex marriage of 2014 — a trend that reveals itself in the course of the year as obvious and inexorable. At the risk of exposing myself as the fuddy-duddy I seem to have become, I hope not.

This is, I confess, not entirely logical and a tad hypocritical. At the risk of exposing myself as not the total fuddy-duddy of my children’s dismissive imaginings, I have done my share of inhaling, though back in the age of bell-bottoms and polyester.

Ruth Marcus is a columnist and editorial writer for The Post, specializing in American politics and domestic policy. View Archive

Next time I’m in Colorado, I expect, I’ll check out some Bubba Kush. Why not? They used to warn about pot being a gateway drug, but the only gateway I’m apt to be heading through at this stage is the one to Lipitor.

Still, widespread legalization is a bad idea, if an inevitable development. Washington state will be the next to light up, in a few months. A measure is heading to the ballot in Alaska this year, along with measures in Oregon and California. As with gambling — also a bad idea, by the way — more states are certain to feel the peer pressure for tax dollars and tourist revenue.

I’m not arguing that marijuana is riskier than other, already legal substances, namely alcohol and tobacco. Indeed, pot is less addictive; an occasional joint strikes me as no worse than an occasional drink. If you had a choice of which of the three substances to ban, tobacco would have to top the list. Unlike pot and alcohol, tobacco has no socially redeeming value; used properly, it is a killer.

So the reason to single out marijuana is the simple fact of its current (semi-)illegality. On balance, society will not be better off with another legal mind-altering substance. In particular, our kids will not be better off with another legal mind-altering substance.

As the American Medical Association concluded in recommending against legalization in November, “Cannabis is a dangerous drug and as such is a public health concern.” It added: “It is the most common illicit drug involved in drugged driving, particularly in drivers under the age of 21. Early cannabis use is related to later substance use disorders.”

And this point, for me, is the most convincing: “Heavy cannabis use in adolescence causes persistent impairments in neurocognitive performance and IQ, and use is associated with increased rates of anxiety, mood, and psychotic thought disorders.”

Once again, teenage toking was the problem. The decrease in IQ was linked only to those with adolescent marijuana use, not those who started in adulthood.

“Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline,” the study reported. For those who started as teens, stopping didn’t fully restore functioning. The results, the study concluded, “are suggestive of a neurotoxic effect of cannabis on the adolescent brain.”

Please do not argue that Colorado’s law, like those proposed elsewhere, bans sales to those under 21. Ha! I have teenage children. The laws against underage drinking represent more challenge to overcome than barrier to access.

Recreational marijuana sales are underway in Colorado, attracting a new type of tourism to the state. Govbeat's Reid Wilson breaks down four things pot tourists should know about the new laws. (Davin Coburn/The Washington Post)

And although alcohol seems to be the teen drug of choice among the adolescents I know, the more widely available marijuana becomes, the more minors will use it. If seniors in fraternities can legally buy pot, more freshmen and sophomores will be smoking more of it.

And it’s not as if the kids need encouragement. By the time they have graduated from high school, nearly half have tried smoking pot; 16.5 percent of eighth-graders have. More alarming, the number who perceive great risk from regular use has been plummeting, from 58 percent to 40 percent among 12th-graders, according to a study funded by the National Institute on Drug Abuse.

And, that study says, for those who trumpet tight controls on sales to minors, a third of 12th-graders who live in states with medical marijuana and who have used the drug in the past year report that one source is another person’s prescription. Another 6 percent have their own Rx.

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